A former hedge fund manager and the pharmaceutical company he founded are raising eyebrows and ire after raising the price of a drug used to fight life-threatening infections from $13.50 to $750 per tablet.

The New York Timesreports 32-year-old Martin Shkreli, founder and CEO of Turing Pharmaceuticals, raised the price of Daraprim more than 5,500 percent overnight since acquiring the rights to the life-saving medicine last month.

The move increases the average annual treatment cost from about $1,130 to $63,000. Some patients will pay as much as $634,000 for a year’s worth of Daraprim.

Shkreli bought the rights to Daraprim for $55 million on the same day that Turing Pharmaceuticals announced it had raised $90 million from Shkreli and other investors in the start-up’s first round of financing. The drug, which was approved by the FDA in 1953, is used to treat toxoplasmosis, an opportunistic parasitic infection that can cause life-threatening complications in infants and patients with compromised immune systems due to certain cancers and acquired immune deficiency syndrome (AIDS).

Several years ago, Daraprim sold for about $1 per tablet. But the drug’s price has increased as various pharmaceutical companies have acquired the rights to it.

“What is it that they are doing differently that has led to this dramatic increase?” Dr. Judith Aberg, head of the infectious diseases division at the Icahn School of Medicine at Mount Sinai in New York, asked the Times. Alberg said the price hike could force hospitals to use “alternative therapies that may not have the same efficacy.”

When asked why he raised the price of Daraprim so “drastically,” Shkreli defended the move.

“Well, it depends on how you define so drastically,” he told CBS News. “Because the drug was unprofitable at the former price, so any company selling it would be losing money. And at this price it’s a reasonable profit. Not excessive at all.”

While Shkreli conceded that raising the price of a drug more than 50-fold appears “greedy,” he insisted that there are “a lot of altruistic properties to it.”

“This is a disease where there hasn’t been one pharmaceutical company focused on it for 70 years,” he told CBS News. “We’re now a company that is dedicated to the treatment and cure of toxoplasmosis. And with these new profits we can spend all of that upside on these patients who sorely need a new drug, in my opinion.”

The Times notes that Turing Pharmaceutical is far from the only drug company that dramatically raises prices on older medicines, some of them generic. While some price hikes are due to market shortages, other products have been made much more expensive as part of a business strategy of buying old medications and re-branding them as expensive “specialty drugs.”

Cycloserine, which is used to treat dangerous multidrug-resistant tuberculosis, was recently acquired by Rodelis Therapeutics, which subsequently raised its price from $500 for 30 pills to $10,800. Valeant Pharmaceuticals drew the attention of Sens. Bernie Sanders (I-VT) and Elijah Cummings (D-MD) after it raised the prices of heart medications it acquired by 525 percent and 212 percent respectively.

Sanders and Cummings, who are investigating why generic drug prices are skyrocketing, noted how the antibiotic Doxycycline went from $20 per bottle to more than $1,800.

“It is unacceptable that Americans pay, by far, the highest prices in the world for prescription drugs,” said Sanders, an advocate of government-run universal healthcare who is seeking the Democratic nomination for president. “Generic drugs were meant to help make medications affordable for the millions of Americans who rely on prescriptions to manage their health needs. We’ve got to get to the bottom of these enormous price increases.”

The Infectious Diseases Society of America and the HIV Medicine Association wrote to Turing earlier this month blasting the price hike for Daraprim as “unjustifiable for the medically vulnerable patient population” and “unsustainable for the health care system.”

Oncologist Dr. David Agus, a professor of medicine at the University of Southern California, told CBS News that Turing Pharmaceutical’s move amounts to a “predatory practice.”

“It’s inappropriate,” said Agus. “Patients shouldn’t be taxed and charged for future research and development. Patients should pay for the drug they’re getting and what they need in the situation that they are.”

Shkreli is standing by his company’s actions.

“This isn’t the greedy drug company trying to gouge patients, it is us trying to stay in business,” he told the Times. “This is still one of the smallest pharmaceutical products in the world. It really doesn’t make sense to get any criticism for this.”

There is also no doubt that Shkreli has a history of gaining control of drugs and sharply increasing their prices. In 2011 he founded Retrophin, which also acquired older drugs before raising their cost. Retrophin’s board fired Shkreli last year, filing a complaint in Manhattan Federal District Court accusing him of using the company as his personal account to repay angry investors in his hedge fund.

Shkreli denies the accusations and says Retrophin owes him some $25 million in severance pay.

“They are sort of concocting this wild and crazy and unlikely story to swindle me out of the money,” Shkreli told the Times.